A computational device maintains logical mirroring of a first file system with a second file system. The system may include a communication circuit to provide wired or wireless communication between the sensor and the receiver. The stopper film is made of an SiCN film having a low optical reflectance, thereby causing it to serve as an antireflective film when the photoresist film is exposed. The aromatic moiety may be reversibly oxidizedreduced at a potential slightly higher than the working potential of the positive electrode in the lithium ion battery. In the fourth step, the chosen user-purpose code is modified so that, when executed, it reads a value from the memory location and uses it in useful calculation.